When data is communicated between various parties, it is common to establish an understanding of the potential structure, interrelationships, and/or allowable forms of such data. This understanding may be captured and defined within a specification and/or schema. A schema is a way to define the structure, content, and to some extent, the semantics of data. With a defined schema, each party can create instances of data structures that conform to that schema and exchange them, such that others will be able to use that same schema to correctly interpret each instance. Schema languages include extensible markup language (XML) Schema (XSD), as a schema language for XML, data definition language (DDL), as a schema language for structured query language (SQL), or common business-oriented language (COBOL) copybook, as a schema language for COBOL. As a system evolves, additional schema versions may be created to support changing requirements for the system.